620991 has 12 divisors (see below), whose sum is σ = 1025232. Its totient is φ = 354816.

The previous prime is 620981. The next prime is 620999. The reversal of 620991 is 199026.

It is a happy number.

620991 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 620991 - 2¹⁰ = 619967 is a prime.

620991 is strictly pandigital in base 7.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (620999) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4866 + ... + 4991.

It is an arithmetic number, because the mean of its divisors is an integer number (85436).

2⁶²⁰⁹⁹¹ is an apocalyptic number.

620991 is a deficient number, since it is larger than the sum of its proper divisors (404241).

620991 is a wasteful number, since it uses less digits than its factorization.

620991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9870 (or 9867 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 620991 is about 788.0298217707. The cubic root of 620991 is about 85.3155972389.

The spelling of 620991 in words is "six hundred twenty thousand, nine hundred ninety-one".